Bottle-handling equipment, such as closure-applying capping machines, must be configured for reliable, high-speed handling of bottles or like containers. While the particular configuration of such an apparatus will depend upon the specific bottles being handled, and the specific closures which are being applied thereto, many applications require that each individual bottle be restrained against rotation, about its own vertical axis, during application of an associated closure. Ordinarily this is accomplished by positioning each bottle in a respective pocket at the periphery of a rotatable star wheel of the apparatus, with the star wheel including an arrangement whereby the bottle is restrained against rotation. As the bottle is moved by the star wheel, a closure is applied to the bottle, and a capping head of the apparatus rotates the closure (while the bottle is held against rotation) for application to the bottle. The bottle is typically subsequently transferred to an output star wheel of the apparatus for subsequent handling, packaging, storage, and shipment.
In order to restrain each bottle against rotation as a closure is applied thereto, current capping machines are typically provided with a flexible belt which extends generally about the bottle-receiving star wheel of the capping machine. This belt, typically formed from suitable elastomeric material, is positioned so that a portion of the belt extends within each of the pockets defined by the periphery of the star wheel. Thus, as a bottle is moved into one of the pockets, it engages and displaces the segment of the belt extending within that pocket, thereby providing the desired restraint against rotation of the bottle as it is frictionally strained by the belt.
While the above-described arrangement for restraining bottles is widely employed, experience has shown that the bottle-engaging belt does not always restrain bottles against rotation as desired. Because such belts are subject to stretching, attendant to deflection by the bottles received in the star wheel, periodic adjustment of the belt tension is required. Additionally, the rate at which such stretching occurs can vary, thus undesirably resulting in inconsistent frictional forces between the flexible belt and the associated bottles. The inevitable build-up on the flexible belt of product being placed in the containers further contributes to inconsistent frictional forces, including undesired slippage of the bottles relative to the belt. Replacement of the belt attendant to wear or breakage has proven to be undesirably time-consuming, detracting from machine productivity by the required "down time" for belt replacement.
The present invention contemplates an arrangement for gripping bottles or other containers in a bottle-handling apparatus which promotes consistent, reliable handling of the bottles, while facilitating efficient maintenance attendant to normal wear.